Malawians staying along the shores of Lake Malawi have of late been viewing with amazement the turning of clear waters in some parts of the lake to green.
From a lay man’s point of view, they have been speculating on what the greening of the water was all about. Fish mongers feared it could affect the livelihood of fish in the lake which are a source of significant income and food.
Numerous enquiries by concerned citizens about the issue were also directed at Minister of Forestry and Natural Resources, Nancy Tembo. After consulting experts in her ministry, Tembo was comfortable to explain the situation.
“According to our experts, the greening is caused by a phytoplankton bloom of the cyanobacteria type (kang’ona). It is toxic and itchy. When swallowed in large volumes, it can lead to death especially in kids.
“This is the case even in Monkey Bay because of the heavy winds on the lake which have prevailed for over two weeks,” explained Tembo.
The experts further say that the persistent south-easterly winds coupled with low water temperatures during this time of the year induces mixing of nutrient rich bottom waters especially in the southern end of the lake resulting in the water becoming eutrophic.
“This phytoplankton bloom is a natural phenomenon that periodically occurs in the lake. We had it in 2009, 2013 and 2019,” added Tembo.
The greening of the water fades away within a week or two.